[PATCH AUTOSEL 6.1 24/26] ext4: only check dquot_initialize_needed() when debugging

Sasha Levin
2023-06-16T10:31:31Z

From: Theodore Ts'o <tytso@mit.edu>

[ Upstream commit dea9d8f7643fab07bf89a1155f1f94f37d096a5e ]

ext4_xattr_block_set() relies on its caller to call dquot_initialize()
on the inode. To assure that this has happened there are WARN_ON
checks. Unfortunately, this is subject to false positives if there is
an antagonist thread which is flipping the file system at high rates
between r/o and rw. So only do the check if EXT4_XATTR_DEBUG is
enabled.

Link: https://lore.kernel.org/r/20230608044056.GA1418535@mit.edu
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/ext4/xattr.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index fddde5045d0c8..51d642a95bd29 100644
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -2006,8 +2006,9 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,
else {
u32 ref;

+#ifdef EXT4_XATTR_DEBUG
WARN_ON_ONCE(dquot_initialize_needed(inode));
-
+#endif
/* The old block is released after updating
the inode. */
error = dquot_alloc_block(inode,
@@ -2070,8 +2071,9 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,
/* We need to allocate a new block */
ext4_fsblk_t goal, block;

+#ifdef EXT4_XATTR_DEBUG
WARN_ON_ONCE(dquot_initialize_needed(inode));
-
+#endif
goal = ext4_group_first_block_no(sb,
EXT4_I(inode)->i_block_group);
block = ext4_new_meta_blocks(handle, inode, goal, 0,
--
2.39.2